My Jeep Wrangler Bogging, sputtering and losing acceleration

[workingclass78]

Hey ya'll.

With all the Jeep people in the know around here I am sure I went to the right place for guidance on my ride.

Here is my situation -

1997 Jeep Wrangler 4.0 137,000 mi.

It is strange but my problem is off and on. My Jeep sputters, loses accelation and makes a bubbling popping sound when I hit the gas (also my RPMs drop). Sometimes this is accompanied by my check engine light coming on. In the past year I have replaced my:

Cap, Rotor, plugs, crank sensor, fuel pump, thermostat, cat converter and transmission.

For example, this was happening really bad on and off, then it stopped for a day or two, I then drove over 500 miles through the White Mountains with NO problem, I come home and now this problem is back again and even worse (again off and on but more frequent).

I had Auto Zone hook my Jeep to a computer and it says my Oxygen sensor has an issue. Any opinions?

Could it be my oxygen sensor? If so which one? Or is it something else.
Has any one had this problem?

 

[workingclass78]

Also when this problem happens, there is an exaust/ gas like smell that is really noticable.

Many thanks everyone

 

[TwistedCU]

help?

If the exhaust/gas smell is only present when this is happening, I would bet on it being sensor or computer related. The oxygen sensor could be the culprit, and if the computer said so, fix it first. This is a pretty common sensor to need replacing and it should be inexpensive.


Any relationship to your problem and wet weather or does it happen in dry conditions as well?

 

[workingclass78]

I have not noticed any weather related issues or if it happens more in a certain type of weather. The thing is I had a mechanic deter me from doing the O2 sensor,, because he said it plays no role in the type of problems my jeep is having ( I think he was bs.'ing me), I now have the feeling he just wanted me to put it in his shop. By the way, having 2 o2 sensors and very little cash is there a way to test them or should I just try a 50/50 guess?

 

[whiterubicon]

Could you be getting bad fuel? If the scan came out as your o2 sensor and it comes and goes you might start bu checking your electrical connections for that system. maby clean them with a contact cleaner and then use a dielectric compound keep things sealed. If that don't work pull the sensors and clean the carbon off them. A good mechanic should be able to tell you what sensor is causing the prob.

 

[workingclass78]

My fuel is good. I have a feeling it is an electrical issue regarding the o2 or something related, it is just way to sporatic and random, but when the proble happens, I have to like rev the engine just to get it to move and it bucks and gurgles then lunges forward and loses acceleration and over and over again. I like the advice of taking out the sensros then cleaning them off, that is perfectly in line with budget!!! Then if that does not do it I guess I'll just try to replace the o2 sensors.

Could this be my fuel pump again? That would be a nightmare. Does this sound like a fuel pump issue.

 

[whiterubicon]

if it comes and goes it sounds like an electrical conection to me. check the wireing to the fuel pump if you have doubts but the fuel pump should not make the engine light come on with an o2 code. be carefull cleaning the sensors. chemicals could cause a failure. Check with outhers on here on how to clean them. My idea would be to use a wite brush lightly but I am not 100% sure. Good luck!

 

[_(OIIIIO)_Jeeper]

Milemarker Winches.....worth it?

Mine(2.5L) was doing the same thing. when I had the down stream O2 sensor replaced it cleared up for a couple of months...then came back...funky smell and all......had the 1st shop look at it for the 2nd time and he said it was showing a "lean" condition on the "down stream" O2 again, replaced it with no change.
I'm taking it in to a different shop Monday. The guy I talked to there said it could be a vacuum leak causing a it to show a lean condition then the Comp. tries to correct it and everything goes hay-wire from there.

I'll let ya know what I find out.

 

[mud4feet]

My '03 TJ has done the same thing to me in the past (hasn't happened in quite a while). Puzzled the bejeebers out of me. The code I got read "No. 3 cylinder misfire" and I thought, No Shite! Has happened a total of maybe 3 times (in 40K miles) and cured itself every time, but is indeed worrysome. I'll be watching this thread and digesting the sage advice for future reference. Y'all are great.

mud

 

[workingclass78]

Well I'm gonna try cleaning the o2's and will begin checking wire connections. Can anyone add to the insight regarding cleaning o2 sensors how to etc.? also, to reiterate: will a shot o2 cause the issues I described, what does a bad o2 do? I even unplugged mine and rev'd the engine and it gave no indication of trouble/additional trouble. argh.

Thanks you guys rock!

 

[pghpenna]

I had about the same problem with my gals 93 Yj, it turned out to be a disconnected hose from the two roll over vent valves on the gas tank. If you take your gas cap off a few hours after driving and don't get a hiss this could be your problem. Frank

 

[laneiac]

Could your fuel filter be bad?

 

[LBR]

I keep relating this problem with your "snorkle extension" thread info - you like to ford overly deep streams, popped 2 exaust manifolds (probably from the cold water as noted before), etc. - moisture related?? Dampness in the distributor would cause those eratic symptoms. Pull the cap, use compressed air carefully in the base of the distributor to dry out, dry cap terminals, WD-40, or whatever your preference is to dry the inside of the distributor. A sensor or electrical connection that is not 100% weatherproofed and has been subjected to moisture from your stream fording could give eratic signals to the computer - any thoughts on this problem starting shortly after an X-treme Jeep-boating incident?? LBR

 

[Bounty__Hunter]

Could be a vacuum leak, check the MAP sensor especially. Good method to clean the o2 sensors and the rest of the head and exhaust is to use Seafoam available at most parts stores. Suck the described amount through a vacuum line like the brake booster line and follow the instructions.

 

[XJNick]

Hi,

If you had the computer scanned with an OBD-II scanner, it should tell you exactly which of the 02 sensors it is giving the code for.

As for if the 02 sensors could cause those problems I'd say possibly. One thing which can help you out is to see if it only happens after the Jeep has reached operating temperature or does it do it all the time (even if the Jeep is cold)? if it does it all of the time, you can probably rule out an 02 sensor problem, as they are only used by the computer after the Jeep has reached operating temperature. :mrgreen:

Also, I don't think they are that cheap. Last time I checked they cost about $70 each.

-Nick :!:

 

[Vic_The_Jeeper]

Hello WorkingClass78,

I know this is long but worth the read:

Try this. Unplug one sensor and see how it runs if no change then plug it back in and unplug the other. Try starting it again if it changes then you know which one is bad. In no change still, then I would suggest checking the vacuum tube on top and see if any are cracked, split, or unplugged. That would cause you to run rich.
I think it is going to be a series of problems and not just one. That was the issue with my 94 Jeep Wrangler Sahara. It hesitated, lost power, and smelled rich. Originally when I first changed my spark plugs, they were pretty bad. Even though I changed them with new ones the problem still persisted. I changed the cables and although it helped out, the problem still persisted. I also checked some sensors like MAP sensor, O2 sensors, Throttle Body Position sensor, and Crank Shaft Position sensor but no fix. Try these basic diagnostic steps:

I posted this in another forum:

"So I stopped messing around and went through the four steps of diagnosing a problem. The four basic elements that are needed to make an engine run are 1)fuel 2)compression 3) timing and 4) spark.

- I checked the fuel pressure by plugging in a fuel pressure gauge on the fuel rail. That was good.

- I then checked compression in the cylinders. That was good.

- So then I checked timing. Even though a little off, not enough to stop it, so in the end that was good enough. (on a side note, on my year model Jeep, only a licensed dealer mechanic can adjust the timing via their specific computer. A regular mechanic couldn't get into that function.)

- Finally I checked spark (One of the four important elements needed to make an engine do what it does). We had a weak spark. (If the spark is bright blue it's good, if it's yellow then it's not good enough to ignite every time). So that leads down to not getting enough volts to ignite a strong spark in the spark plug, thus causing the popping from the fuel not getting ignited every time and causing intermittent power loss. Tracing back the source of the problem, it could either be the distributor cap, rotor, ignition coil, or ignition module. Mine was the ignition coil! I changed that and it ran great!

My problem now lies in that the ignition coil keeps going out. I replace it and it fires up like a champ! After a while, the coil goes bad and needs to be replaced. So I have an electrical problem before the coil.

I know my alternator is good and the volts going through are ok. I'm pretty sure my voltage regulator is in the alternator. So it can either be the ignition module or there is a short somewhere in the wiring. I'm contemplating replacing ALL of the wiring since the kits now-a-days are pretty easy to install besides having to run the wires through tight places."

I hope this helps you! Remember, go through all of the steps. It might be more than one problem. You don't always get codes for what can be wrong.

Good luck!
-Vic_the_Jeeper!

 

[woodie92]

Hey ya'll.

With all the Jeep people in the know around here I am sure I went to the right place for guidance on my ride.

Here is my situation -

1997 Jeep Wrangler 4.0 137,000 mi.

It is strange but my problem is off and on. My Jeep sputters, loses accelation and makes a bubbling popping sound when I hit the gas (also my RPMs drop). Sometimes this is accompanied by my check engine light coming on. In the past year I have replaced my:

Cap, Rotor, plugs, crank sensor, fuel pump, thermostat, cat converter and transmission.

For example, this was happening really bad on and off, then it stopped for a day or two, I then drove over 500 miles through the White Mountains with NO problem, I come home and now this problem is back again and even worse (again off and on but more frequent).

I had Auto Zone hook my Jeep to a computer and it says my Oxygen sensor has an issue. Any opinions?

Could it be my oxygen sensor? If so which one? Or is it something else.
Has any one had this problem?

had the same problem, ran trouble codes and it was the tps.... i was running the 2.5 and had a spare 4.0 tps... put it in and problem solved all of this with a bad 02 sensor( only because i had ripped the wires out clearing a tree stump coming out of a pond!) none the less tps was intermitent and the problem. hope it helps

 

[dandoc]

WOW! This is a zombie thread revived from the crypt! I imagine in the nearly four years since this thread was started, workingclass78's problem has been solved.

 

[woodie92]

lol i didn't even look at the dates!!!!!! i was just pluggin away too... manp0p

 

[wrang97]

4th owner to wrangler 97. Had problems with backfiring/sputtering/loss acceleration. went to every site tracking down this problem. Finally followed steps to clean PCM (powertrain control module located above battery on passenger side) connectors, and secured them with wireties. Also secured two connectors to the right with wireties and padded to firewall. Also noticed problem existed as with others when turning, so I repositioned the battery with it's own clamps to keep it from shifting/rubbing against wire harness to pcm. so far this appears to have helped!!